A substance has a half-life of 100,000 years and an initial mass of 1,000 grams. how many years will pass before only 250 grams of the substances parent material is left?

What are some associated with obtaining and using coal

Which molecule is used by so as an energy source

A cyclist rode at an average speed of 15 mph for 30 miles. How long was the ride? A) 2 hours B) 1 hour C) 0.5 hours D) 3 hours

1 pts A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed.

Blood clots form using which of the following components? Check all that apply. fibrin platelets blood clotting factors blood cells

Why is it important for cell division to occur?

Which of the following is true about the hierarchy or organization of life? (Check all that apply) A. Changes at the lowest level can affect the more complex levels. B. Cells make up tissues. C. Cells are made up of macromolecules. D.

Unwrapped food placed in a freezer experiences dehydra - tion, known as "freezer burn." why?

Which muscle group has the largest increase in circumference when contracted? Why do you think this occurred?

You are caring for a client who is a refugee from haiti. the family has been displaced because of an earthquake in their country. the client has healing fractures on his right arm as well as fractured ribs.